Homework Help:
Magnetic Moment of a spinning shell

I split the sphere into infinitely small loops of current (from top to bottom) and add them up. I set my origin on the center of the sphere and integrate with respect to y from 0 to R times two to get the entire sphere.

This is incorrect, and I have a suspicion it has to do with the "dA" part.

If you don't mind his handwriting, http://nebula.deanza.fhda.edu/physics/Newton/4B/MagneticMomentSphere.jpg [Broken] is the correct way to do the problem. I am rather uncomfortable integrating over angles, so I opted for a different way.